Sodium lactate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April 1992 - May 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

the limit concentration tested was 10,000 mg/L instead of max 1000 mg/L as given in the test guideline at that time (max 100 mg/L in the present test guideline). This is not expected to influence the validity of the test.

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): sodium L(-) lactate
- Physical state: aqueous liquid
- Analytical purity: 60%
- Composition of test material, percentage of components: 60% sodium lactate, 40% water
- Lot/batch No.: Ni 120 E
- Expiration date of the lot/batch: 1997

Analytical monitoring:

yes

Details on sampling:

The actual concentration of soluble sodium in the test solution was determined by chemical analysis. At t= 0 hours, samples of ca. 100 mL were taken from the control medium and the newly prepared test solution of nominal 10,000 mg/L. At t= 48 hours samples were taken from the same spent solutions. All samples were filtered through a 0.45 µm membrane filter. The samples were then transferred to polyethylene bottles and a 100µl aliquot of HNO3 was added to each samples for conservation. The samples were stored in a refrigerator until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A quantitiy of 10,000 mg sodium L(-)lactate was accurately weighed out and dissolved in 1,000 mL of dilution water (DSWL). This solution was used as test solution.
- Controls: Dilution water (DSWL)
- Evidence of undissolved material (e.g. precipitate, surface film, etc): test solutions appeared to be completely clear (visually assessed); after 48 h the test solutions were slightly turbid.

Test organisms (species):

Daphnia magna

Details on test organisms:

The daphnids were cultured in the laboratory under standard conditions according to the principles of NPR 6503. The animals were less than 24 old at the beginning of the test. No food was given during the test.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

None.

Hardness:

203 mg/L expressed as CaCO3

Test temperature:

20 ± 1 °C

pH:

7.4–8.2

Dissolved oxygen:

start: 8.4 mg/L in control, 8.6 mg/L in test solution
end: 8.7–9.1 mg/L in control and 5.2–5.4 in test solution

Nominal and measured concentrations:

Nominal: 0 and 10,000 mg test substance/L; equal to 0 and 6,000 mg sodium L(-) lactate/L
Measured start: based on Na: 0 and 10,400 mg test substance/L; equal to 0 and 6,240 mg sodium L(-) lactate/L
Measured end: based on Na: 0 and 9,100 mg test substance/L; equal to 0 and 5,460 mg sodium L(-) lactate/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, fill volume: 150 ml all-glass beakers, fill volume 100 ml
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 8
- No. of vessels per control (replicates): 8

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dutch Standard Water (reconstituted water), prepared from Linschoten ground water
- Metals: Na 1.04 mmol/L, K 0.21mmol/L, Ca 1.33 mmol/L, Mg 0.70 mmol/L
- Chlorine: 2.54 mml/L

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 h light, 8 h dark with transition periodsof 30 minutes

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilization at 24 h and 48 h. At the same time the condition (swimming behaviour, colour or any other visually observable morphologial or behavioural criterion) of the mobile animals was compared with that of the test animals.

TEST CONCENTRATIONS
- Test concentrations: limit test, only one concentration tested (10,000 mg test substance/L)
- Results used to determine the conditions for the definitive study: a preliminary range-finding test indicated that no toxicity was to be expected at 10,000 mg/L.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 10 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 10 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 6 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: sodium L(-) lactate

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 6 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: sodium L(-) lactate

Basis for effect:

behaviour

Details on results:

- Behavioural abnormalities: none
- Observations on body length and weight: not done
- Other biological observations: There were no immobile animals in the control vessels and in the solutions of 10,000 mg/L. The condition of the surviving animals was equal to that of the control animals (visually assessed). The NOEC for mobility and condition are therefore 10,000 mg/L based on the test material equal to 6000 mg sodium L(-) lactate/L. See Table 1 in 'Any other information on results incl. tables'.
- Mortality of control: no mortality in control
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- Effect concentrations exceeding solubility of substance in test medium: none

Table 1. Number of mobile animals (Daphnia magna) at one concentrations of Sodium L(-) lactate and after several exposure times.

Time  (h)	Nominal concentration of test substance (mg/L)
	0	10,000
0	40^a)	40^a)
24	40^a)	40^b)
48	40^a)	40^b)

 

^a)Condition of all test animals, visually assessed, normal (=good).

^b)Condition of all test animals, visually assessed, equal to that of the control animals.

Validity criteria fulfilled:

yes

Conclusions:

No effects on mobility or behaviour were reported at concentrations as high as 6000 mg sodium-L-lactate/L. Sodium-L-lactate is not acutely toxic to Daphnia magna.

Executive summary:

The acute toxicity of sodium-L-lactate to the freshwater crustaceanDaphnia magnawas determined as decribed in the OECD guideline no. 202 and according to the OECD principles of Good Laboratory Practice.

The test was carried out with 8 × 5 daphnias (eightfold test solutions) for the test concentration and control, and the test solutions were not replaced.

The exposure duration was 48 hours.

The nominal concentrations tested was 10,000 mg/L based on the test material, which equals 6000 mg/L sodium-L-lactate.

At the start of the test the test substance appeared to be completely dissolved (visually assessed).

The actual concentration of sodium-L-lactate in the test solutions was determined at the start and end of the test by measurement of the sodium concentration (ICP-AES). They were between 104 and 91 % of the nominal concentrations (average 97.5 %).

No effects of sodium-L-lactate on mobility or condition of the daphnids were observed.

The results of the test were (in nominal concentrations):

48-h NOEC (mobility = 48-h EC₀): 6000 mg sodium-L-lactate/L

48-h NOEC (condition): 6000 mg sodium sodium-L-lactate/L

Description of key information

No adverse effects of Sodium (S)-lactate were observed in a short-term toxicity test with the fresh-water crustacean Daphnia magna at concentrations up to 6000 mg/L. Based on the absence of effects by Sodium (S)-lactate at concentrations 60 times the limit concentration (100 mg/L) it can safely be concluded that no effects occur at the limit concentration either. Therefore, no hazard has been identified.